The P2P streams tend to be much higher quality. You'll need to run the Ace Streams Engine application before you start XBMC for these sort of links to work. Check the list of all installed Android applications and click on the app first. If you can't see it, try looking for Torrent Stream Controller. The one downside is that you need other people viewing the same event for it to work.
Flash - most often lower quality, doesn't matter who else watches it at the same time normally
P2P/Torrent/SopCast - normally three to ten times higher quality, but it relies on other people sharing the data they've downloaded with you. Extreme example - England vs Germany World Cup Football Final=absolutely fine. Venezuala vs Outer Mongolia underwater basket weaving semi-final - not enough viewers to keep the video stream alive.